There isnt going to be a site where you can find your work history online. Just do the best you can to remember when you started working at a job and when you left, it doesnt have to be perfect. Employers are just looking for what type of work you previously did, how long you stayed with each company, and your reason for leaving. When they call for refrences they arent checking your dates.
Access site below because you can find there patterns of resumes and plenty of information regarding this subject. Good Luck ! assistantresume.org